1. Field of the Invention
This invention relates to the field of optical components and communication systems and, more particularly, to the filtering of optical signals and wavelength division multiplexing and demuliplexing.
2. Background of the Invention
Today""s high speed telecommunication networks employ optical fibers as the medium for transmission. These networks can extend to thousands of kilometers and can have hundreds of nodes. The capacity of optical networks has been increased by transmitting channels using wavelength division multiplexing (WDM). To increase the flexibility of theses networks there is a need of making the WDM dynamic.
In accordance with the current invention, a dynamically reconfigurable optical add/drop multiplexer is used to add/drop a single or plurality of wavelengths from a set of predetermined wavelengths. The optical beam delivered through an optical fiber, a waveguide or other means impinges on a narrowband optical filter. The filter is designed to pass the light of a particular wavelength and reflects the light of other wavelengths. At any filter a wavelength is dropped and the same wavelength can be added back. To drop a plurality of wavelengths the beam is passed through a plurality of filters. The said filtering device is made out of a set of filters each passes a particular wavelength. There are two implementations of the said invention.
The first embodiment of the invention is for dropping, and possibly adding, a single wavelength from a predetermined set of wavelengths. This can be done by moving the filtering device across the optical beam and placing the desired filter in its path or by redirecting the optical beam through a set of mirrors to align it and pass it through the proper filter.
The second embodiment of the invention is for dropping, and possibly adding, a single wavelength from a predetermined set of wavelengths. This can be done by using a stationary narrow band optical filter array device and actuated mirrors that route the optical beam.
The third embodiment of the invention is for dropping, and possibly adding, a plurality of wavelengths. This can be achieved by routing the beam through a set of actuated mirrors through the desired filters.